It is common to design portable devices with an enclosed battery compartment, or with means for attaching a battery pack (or simply “battery”) to the portable device. In many devices the battery can be recharged either by removing the battery and placing the battery in a charger, by connecting the portable device to a charger, or in some cases, placing the portable device with the battery together into a charger.
Many portable devices, such as, for example, portable two-way radio devices and accessories, are designed to be operated by personnel wearing gloves. As such having to take a small, handheld device apart to remove a battery for charging, or connecting a cable to a small connector (e.g. micro USB) is not optimal. Accordingly, such devices are often designed to have prominent charger contacts on a surface of the device so that the device including the battery can easily be placed into a charger without need for fine manipulations. However, such exposed contact can present an opportunity for contact with electrically conductive items, potentially creating a short circuit between the positive and negative charger contacts. When this occurs, if it occurs, an undervoltage protection circuit in the battery can open an undervoltage switch, removing power from the device. Typically, the undervoltage switch will remain opened, even though the short circuit is removed from the charger contacts, due to the load presented by circuitry in the device. When this occurs, the battery must be momentarily removed from the device in order to reset the protection circuitry. Cleary, having to remove the battery from the device to reinstate battery operation can be considerably inconvenient, particularly if the device is a portable two-way radio device being used by a public safety operator.
Accordingly, there is a need for a way to prevent short circuit conditions from tripping protection circuitry in the battery while still preventing a short circuit from interrupting device operation.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.